Estimating the Sensitivity of Storage capacity to the Fraction of Free Pore Volume and Surface Adsorption in Mafic Rocks: A case study from Deccan Basalts, India

Earth’s basaltic repositories are among the premier CO2 storage spaces. The Deccan Traps in India, the world’s largest basaltic flow deposits, offer one of the viable options for CO2 sequestration due to their extensive availability and the heterogeneity of texture and mineralogy. Laboratory investigations and field implementation of CO2 treated basalts show the release of divalent cations upon reaction with and formation of stable carbonates upon reaction with CO2 and brine. However, this varies with the varying composition and texture of the samples atspecific conditions of pressure, temperature, and CO2 injection rates. To guarantee long-term sustainability, it’s crucial to formulate a viable model that includes using the sample with maximum divalent cations, high porosity, and permeability and calculate its storage capacity.

 

This research work utilizes the samples collected from the field to calculate their storage capacity and compare how textural difference can bring about change in storage mechanism of CO2 in the sample. The comparison between storage capacity calculated for samples showed that each mechanism plays a crucial role in CO2 storage in basalts of varying composition and porosity. Moreover, through in-situ experiments, we can identify the mechanism best suited for the basalts of the Deccan Trap formations. Thus, results acquired from storage estimation and in-situ experiments will together guide to make mindful decision while choosing the sites for CO2 capture for maximum storage and avoid any potential leakage risks or gas escape.